Thread wound golf balls are classified roughly into two types, e.g. a golf ball using a solid center (center made of a rubber composition) and a golf ball using a liquid center.
Regarding the former thread wound golf ball using a solid center, amount of spin is too large so that the flying distance becomes short, thereby imparting hard feeling (hit feeling). Therefore, professional golfers and advanced players do not like the golf ball with a solid center.
The latter liquid center is classified roughly into two types, e.g. a liquid center containing paste in which a filler is formulated to adjust a specific gravity and that containing liquid which is similar to water. When using the liquid which is similar to water, a rubber center bag for covering (containing) liquid must have a certain degree of a specific gravity so that the hardness of the center bag becomes high, thereby imparting hard feeling in comparison with the center containing paste. Further, the amount of spin becomes too large so that the flying distance becomes short.
To the contrary, regarding the liquid center containing paste in which a filler is formulated to adjust a specific gravity, the paste itself has a certain degree of a specific gravity so that the specific gravity of the center bag can be decreased and the hardness can also be decreased, thereby softening the center entirely.
Accordingly, hit feeling becomes soft and amount of spin does not become too large, which results in good flying performances. Therefore, professional golfers and advanced players like the golf ball with a paste type liquid center.
However, regarding the liquid center containing paste, scattering of quality (e.g scattering of weight, inclusion of air, deviation of center of gravity in the liquid center due to separation of paste into water and filler, etc.) is liable to be arisen, thereby influencing on the flying performances. Therefore, the flying performances are liable to be scattered.